11D428 Explained

11D428A-16
Country Of Origin:	Russia
Date:	1993–1997
First Date:	1997-10-05 (Progress M-36)
Designer:	NIIMash
Purpose:	RCS thruster
Predecessor:	11D428A
Successor:	11D428AF-16
Status:	In Production
Type:	liquid
Fuel:	UDMH
Oxidiser:	N2O4
Mixture Ratio:	1.85±0.15
Cycle:	pressure fed
Combustion Chamber:	1
Thrust(Vac):	129.16N
Chamber Pressure:	0.88MPa
Specific Impulse Vacuum:	291isp
Restarts:	500,000
Dry Weight:	1.5kg (03.3lb)
Used In:	Soyuz since Soyuz TM-28 and Progress since Progress M-36

The 11D428A-16 (manufacturer's name RDMT-135M) is a liquid pressure-fed rocket engine burning N₂O₄/UDMH with an O/F of 1.85. It is used for crew-rated spacecraft propulsion applications. It is currently used in the KTDU-80 spacecraft propulsion module. The previous version, the 11D428A (manufacturer's name RDMT-135) is still used as the reaction control system thrusters of the Zvezda ISS module.The 11D428A-16 generates 129.16N of thrust with a chamber pressure of 0.88MPa and achieves a specific impulse of 291isp. It is rated for 500,000 starts with a certified ignition time of 0.03 seconds to 2000 seconds. Each unit weights 1.5kg (03.3lb).

Versions

This engine has been used with certain variations in the crewed Russian space program since the Salyut 6 in Soviet times. The three main versions are:

• 11D428: Delivered in 1970 for use in Salyut 1.
• 11D428M: Version developed for the Yantar-2K platform. It reached space on the first launch, Kosmos 697 on August 6, 1974.
• 11D428A (AKA RDMT-135): Version developed for the Soyuz 7K-S, it flew on Kosmos 670, Kosmos 772 and Kosmos 869. Later used on the KTDU-426.
• 11D428A-10: Thruster used on the Zvezda ISS Module. Originally developed for the Mir Core Module.
• 11D428A-14: Thruster used on the Zvezda ISS module.
• 11D428A-16 (AKA RDMT-135M): Improved specific impulse version. Used on the KTDU-80 since Soyuz TM-28.
• 11D428AF-16:Thruster version developed for the Fobos-Grunt planetary sample mission.

Engine	11D428A	11D428A-16	11D428AF-16
Development	1968–1974	1968–1977	1993–1997
Engine Type	Liquid pressure-fed rocket engine
Propellant	N2O4/UDMH with 1.85 O/F ratio
Thrust	130.5N	129.16N	123.5N
isp	1:56 Exp. Nozzle:290isp 1:150 Exp. Nozzle:302isp	291isp	306.2isp
Nominal Inlet Pressure	1.77MPa	1.76MPa	1.47MPa
Nozzle	1	1	1
Burn time	570s	2700s	50,000s
Ignitions	500,000
Ignition time	0.03 to 2000s
Mass	1.2kg (02.6lb)	1.5kg (03.3lb)	1.9kg (04.2lb)
Length	274mm	289.5mm	372mm
Diameter	98mm		157.4mm
Uses			Fobos-Grunt
References

See also

• KB KhIMMASH
• KTDU-35
• KTDU-80
• Soyuz-T
• Soyuz-TM

External links

• KB KhIMMASH Official Page (in Russian)